<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="app">   
    <!-- app内的内容都叫做虚拟DOM -->
    {{ msg }}
  </div>
</body>
<script src="../../lib/vue.global.js"></script>
<script>
  Vue.createApp({
    data () {
      return {
        msg: 'hello vue3'
      }
    }
  }).mount('#app')
</script>
</html>